When a computer that has plural CPUs (Central Processing Unit) realizes a virtualization system including plural virtual nodes, one of the CPUs is allocated to each virtual node. Then, by executing a program by the allocated CPU, the virtual node is realized. In addition, communication between virtual nodes is performed by a mechanism of an internal virtual network.
Also in such a virtualization system, there is a case where communication efficiency decreases due to a virtual node that is a bottleneck. However, unlike in the case of a physical network, it is impossible to identify the bottleneck by monitoring transmission rates.
Moreover, in the virtualization system, there is a case where plural virtual nodes become bottlenecks simultaneously. In other words, there is no technique to make it easy to find bottlenecks that occurred simultaneously.
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